As soon as I see it on the map, I have to go there. We're meandering down the eastern seaboard of America from New York to Miami, and just off the Carolina coast I've spotted a 100-mile road to nowhere: an immense curve of highways, bridges and causeways that fizzles out on an island called Ocracoke.

It looks like a place that will be full of people who really want to be there. Only an idiot could end up on the island by accident. But then again, that kind of idiot should be worth meeting too.

We drive on to the chain of islands at Kitty Hawk, North Carolina, the quiet spot the Wright brothers chose to try out their first aeroplane. However, like all airports, it has become a little busier in recent years. Now there are nose-to-tail cars nudging over the bridge and a road sign is pointing us to a place called Nag's Head. It sounds less a chain of idyllic islands than the immense driveway to a pub.

However, once the highway has got all the neon-lit forecourts out of its system, the islands live up to their name. They're called the Outer Banks and are just that - sandbanks with a road along the middle, dunes and waves on one side and a placid lagoon on the other.

We drive south, almost eerily alone. From time to time a village appears, a collection of what the locals call cottages but which are cottages in the same way a half-pound cheeseburger is a between-meals snack. They're immense, four-storey wooden constructions teetering on high stilts, as if the sand had been washed away from under them - which might well be the case. As one website puts it: 'For thousands of years the barrier islands have survived the onslaught of storm, wind and sea.' Scary words for architects and estate agents.

The road bends west at Cape Hatteras and suddenly stops short at a ferry terminal. Seems we can't drive all the way to Ocracoke, after all. I feel my wallet cringing at this unexpected turn of events. We're in America, the capital of capitalism, and are a captive market. We either take the ferry or turn round and drive back two hours north. This is going to cost a fortune, right? Wrong. It's free.

'Have a good one,' the weather-beaten guy at the ticket booth tells us and we roll on to a tiny ferry. A few other drivers join us and we set off; the boat has no real timetable and leaves when it feels like it. As soon as we're clear of the harbour area, a dolphin arches its dorsal fin out of the water and gambols in our bow wave as we cruise into the setting sun. I tell the dolphin it's being a tourist office cliche, but it insists on hanging round to be photographed.

Ocracoke comes into view, yet another sand dune tapering into the sea, and the ferry drops us off in the middle of nowhere; the village is 16 miles further on. It really is at the end of the trail.

We've booked a room at the Blackbeard's Lodge, a rangy wooden house festooned with porches and balconies. The lobby is dominated by a life-size wooden pirate who seems to be keeping his good eye on us so that we don't steal one of the antique lamps.

We shower and drive half a mile to a pub where, in the parking lot, I see a car that not only has all its windows open, but also one of its doors. This island is so laid-back it's almost asleep.

In the pub, a tattooed singer is belting out her songs to an audience of loud studenty types swilling beer and families eating monster burgers and Shrek-sized shrimps. Over a fruity Yuengling lager ('America's oldest, since 1829'), I read up on our pirate host.

It seems that in the early 18th century Edward Teach, alias Blackbeard, ruled the waves around the island. Until, that is, the British navy tricked him into an ambush, inflicted 25 stab wounds and five bullet holes on him and hung his head from their bowsprit as a trophy. That's what you call getting tough on crime.

The guidebook says that Ocracoke's inhabitants in those days spoke a Cornish patois and that because of the island's isolation the accent can be heard today. We listen out for traces of a Cornish twang, but our waitress is from Virginia and the lads at the next table are bantering in pure testosterone.

Next day, we continue our hunt for the local accent. Admittedly, the beach is not the best place for socio-linguistic research, but after the previous day's long drive, I'm longing to splash in the sea. There is officially nowhere better in the US to do so, either - this year Ocracoke was named America's best beach in an annual survey by 'Dr Beach', aka Dr Stephen Leatherman, director of Florida International University's Laboratory for Coastal Research. He uses 50 criteria, from water and sand quality to cleanliness and management. Ocracoke's triumph was a shock, the first time any beach outside Florida or Hawaii had won.

Bizarrely, as we tramp over the top of the dune, the first thing we see is a line of 4WDs along the seashore, with people practically fishing from their rear doors. But the beach itself is an apparently endless expanse of white sand that dwarfs even the biggest 4WD. The ocean is warm and the waves just the right size for bodysurfing and some general leaping about while hanging on to your swimmies. The good news is that a judge has since ruled that 4WDs will no longer have access to the beach, on the grounds that rare plovers nest there. Go plovers, I say.

Back in the village, we eat local seafood. I've always found in America that wherever there are tourists, decent food is never far away. How can you argue with grilled hunks of locally caught fish with baked potatoes and a salad?

Here, we strike lucky. Our waitress is an island resident, a schoolteacher who moonlights during the summer season. She tells us that the Cornish accent is called Brogue and that 'hoi toide' is how fishermen refer to the best time to set sail. She doesn't speak Brogue herself, but knows older people who do.

'Go down to the harbour at 4pm,' she says, 'and look for a man cleaning fish.' So just before four, we head to the quayside and spy a deeply suntanned man sitting on a mooring post. Sensing victory, I sidle within range, but quickly realise that I've got it all wrong.

'D'you iknowlidge thit every-thang in mah depoh-sishun is akrit?' he is saying into his phone. If this is a Cornish fisherman, he does a great impression of a Deep South lawyer.

The only place you can be sure to hear the old accent these days is in the University of North Carolina's online sound archive. We log on and listen to some interviews. Islanders call themselves 'O'Cockers' and say 'thar' instead of 'there'. The accent is straight out of an ad for pasties.

We're downloading the voices at a funky little internet cafe, where everyone is so relaxed and friendly that you wonder why you would ever leave.

'Yeah, Ocracoke's cool in summer,' a topless (male) surfer tells us. 'But it shuts up like a clam in winter. And most of the island is less than six feet above sea level, so if you get a summer hurricane or a winter storm ... ' He grimaces and lets us imagine the Atlantic waves disturbing the tranquillity of the cafe porch.

So maybe Ocracoke isn't a place you'd want to stay forever. But for the short time you're there, you feel so cut off from the world that there's nowhere else to go. And you just don't care.

And the runners up

Dr Stephen Leatherman, aka Dr Beach, conducts an exhaustive annual study of America's beaches and sorts them into a league table. This year's number one was Ocracoke, followed by:

· Stephen Clarke's new novel 'Merde Happens' is based on his road trips across America. To order a copy for the reduced price of £9.99 with free UK p&p go to observer.co.uk/bookshop or call 0870 836 0885.